[Mesa-users] Technical issue: calculations going incredibly slow

[Amedeo Romagnolo]

Hi all,

I found out how to overcome this issue. Basically the CPU was indeed
overheating and I set the number of cores to 8 (instead of 12), which made
the whole process much more stable.

For the benefit of everyone that might incur into this problem in the
future, the steps to solve it can be:

   - While running MESA, check on another terminal the CPU/RAM usage by
   running the command "top"
   - If the CPU usage is too high, then run on a terminal  " cat
   /sys/class/thermal/thermal_zone*/temp " (without the " ") to check if your
   temperature (in millicelsius) is higher than 80/85 °C in some of the
   thermal zones
   - If so, if you don't have any external way to cool your PC more, try to
   lower the number of cores by running "export OMP_NUM_THREADS = ... " to
   reduce the stress on your hardware

Thanks to all for your helpful feedback!!

Have a nice day,

Amedeo

On Tue, 4 May 2021 at 12:10, Amedeo Romagnolo <amedeoromagnolo at gmail.com>
wrote:

> Hi Rob,
>
> so, it starts getting slower about 2061763.808 s at model_number 3400.
> Log(dt) is ~ 1.49, which is no sudden change from the previous 1.48 .
>
> Amedeo
>
> On Tue, 4 May 2021 at 11:26, Rob Farmer <robert.j.farmer37 at gmail.com>
> wrote:
>
>> Hi,
>> Okay can you add elapsed_time to your history columns file, this will
>> track the amount of time since the run started (so we can hopefully see
>> when it starts getting slow and by how much).
>>
>> Also when you start a ./rn what timestep does it get to when it slows
>> down?
>>
>> Rob
>>
>>
>> On Tue, 4 May 2021 at 11:16, Amedeo Romagnolo <amedeoromagnolo at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> it doesn't have a fixed time when it slows down per se. It is just after
>>> the first ~10 minutes I initialize the code, be it with ./mk + ./rn or with
>>> ./re . It is regardless of when the star does, be it at pre-MS, MS, or post
>>> MS.
>>> The cpu/ram usage is the following (star is the MESA run):
>>>
>>> [image: image.png]
>>>
>>> And for the record my CPU is anything but poorly performing. Do you
>>> think I should try reducing the cores or something?
>>>
>>>
>>>
>>> On Tue, 4 May 2021 at 11:06, Rob Farmer <robert.j.farmer37 at gmail.com>
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> Can you provide more details? What's the star doing when it starts to
>>>> slow down? How far in the evolution do you get in the 10 minutes? I ran
>>>> your model for ~3500 steps (and also did a ./re) and didn't notice it
>>>> getting slower. How many mesh points/isotopes does your model have when it
>>>> starts getting slower? Did they increase when it did?
>>>>
>>>> If you run top in another terminal while the run is going, how much
>>>> ram/cpu are you using (as a percentage of your system)?
>>>>
>>>> Rob
>>>>
>>>>
>>>> On Tue, 4 May 2021 at 10:23, Amedeo Romagnolo via Mesa-users <
>>>> mesa-users at lists.mesastar.org> wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> here is my problem. I have set a pretty vanilla simulation on MESA
>>>>> (inlists attached), but because of some weird black magic my calculations
>>>>> go fast enough over the first ten minutes, and then they dramatically slow
>>>>> down. And I'm not talking about timesteps, but about the actual calculation
>>>>> time for each timestep.
>>>>>
>>>>> Even more weirdly, if I reset my PC and restart the simulations (./re)
>>>>> the code goes fast for another ~10 minutes and then slows again.
>>>>>
>>>>> I'm using Ubuntu 20.04, and I made sure no other process was running
>>>>> at the same time. And yes: I set the right number of cores.
>>>>>
>>>>> Did this happen to anyone else? Do you have any idea on how to solve
>>>>> this?
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Amedeo
>>>>> _______________________________________________
>>>>> mesa-users at lists.mesastar.org
>>>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>>>
>>>>>
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